The gas adsorption isotherms of cellulose acetate RO membranes were investigated in order to characterize the pores of laboratory prepared membranes. The data showed that before annealing, the molecular structure was relatively homogeneous, but during annealing, the heterogeneity of the membrane molecular structure increased, the micropores were enlarged and thus pore volume and surface area were increased. The nature of the membrane pore structure suggested by adsorption measurements on vacuum dried RO membranes will not, however, be identical to that existing before membrane drying. The water permeability decreased from 278.0 × 10-5 cm3/cm2-sec for unannealed membrane to 9.2 × 10-5 cm3/cm2-sec for membranes annealed at 90°C. Increase of gelation temperature made the resulting membrane possess mesopores in spite of unannealed conditions. The membrane gelation temperature of 20°C showed the characteristics of an ultrafiltration membrane. Gas adsorption experiments using chlorine damaged membranes showed considerable decrease in both pore volume and surface area.
|Number of pages||22|
|Journal||Journal of Membrane Science|
|State||Published - Oct 30 1991|
Bibliographical noteFunding Information:
This research project was supported by the National Science Foundation.
- membrane preparation and structure
- reverse osmosis
- solubility and partitioning
- water treatment
ASJC Scopus subject areas
- Materials Science (all)
- Physical and Theoretical Chemistry
- Filtration and Separation